I have an eight month old large gundog. The problem is we cant get any muscle on him. He as 45 mins of free running each day plus the running around the garden that he does.He as Hydrotherpy swimming once a week.
I have never had a pup before with this problem. We have been to the vets and they can find no reason for it.
Has anyone had this problem before? He is not the first of this breed that i have had, he is my 10th, the breeder is at a lost.
We have tried extra vit e. We are now getting knocked in the showring for the lack of muscles. Help!!

I genuinely wouldn't worry too much at this age BUT if he were mine I'd ease back on the exercise.  I think it too much.  He should still be restricted and if he's legging it round the garden then he won't need so much time free running.  Short on lead exercise will be more useful, and potentially less damaging.

I know you have lots of experience in this breed but have you spoken to the stud owner about dad?  What was he like at the same age?  Some boys go through a real gawky phase and maybe his lines are just different to those you've owned before.  Can you say what breed? Maybe someone will have some direct experience to help :)

He has plenty of time to finish growing, so don't worry too much just now. Even litter mates grow at different rates, and where one can look 'finished' at 8 months another could still look like the runt of the litter if they stood side by side. They can then look very similar a couple of years down the line. This is where the pedigree is handy. If you know the dogs on it, or the breeder and stud do know them, then you are more likely to find out that there were others that grew just the same way.

For instance, I have a bitch here that just grew and grew and at 6 months old was at her adult height. She is still a very leggy girl, but hasn't grown any more since, and she is now 2 years old. A full sister took her time in growing and at 6 months we were worried that she might not make the height. By 2 years old she was in the ring, winning a CC, as she had caught up and matured very nicely.

Give your pup the time he needs to mature. You can do more damage by trying to muscle him up at this age.

At 8 months old he's still a minor puppy, so you wouldn't expect him to be physically like an adult. It's quite likely he's just a slower developer than the ones you've had before.

I agree with others that he is still quite young although I would have thought that he would have some muscle on him. I also have large gundogs and have never had a problem with muscle even when they are going through the gangly stage.
Mine have a mixture of road walking, not too much though at his age, and free running in the forest over different gradients and surfaces.
Does he have any doggy companions? I find that play between them often uses a lot of different muscles that walking alone doesn't do. My best muscle builder for me is swimming and running through water in the river, great for building up muscles and they love it even in this hot weather.
But remember go easy for a few months yet.

Thank you for all your replies, makes me feel alot better. I forget that he is still a baby even if it is a big baby. He also as 6 other dogs to play with.
I have always had the feeling that we would not do very well as a puppy but when he grows up that will be a different story, again thank all.